Test your diagnostic skills in our regular dermatology quiz. What is the cause of these irritable scalp lesions?
A 78-year-old man presents with multiple crusted irritable lesions on his scalp that he says have been slowly worsening over the past year (Figure). The lesions are irritable, causing him to pick and scratch. He has generalised sun damage and has had a history of actinic keratoses, basal cell carcinoma (BCC) and squamous cell carcinoma (SCC).